检索结果-内蒙古大学图书馆

Influence of cetane number improver on performance and emissions of a common-rail diesel engine fueled with biodiesel-methanol blend

引用

能源前沿 2011年第4期5卷 412-418页

作者： Wu YU Gen CHEN Zuohua HUANG State Key Laboratory of Multiphase Flow in Power Engineering Xi'anJiaotong University Xi'an 710049 China

In this paper,the effect ofcetane number (CN)improver on performance and emissions,including particulate number concentration and size distribution,of a turbocharged,common-rail diesel engine fueled with biodiesel-methanol were *** volume fractions (0.3％ and 0.6％) of CN improver were added to BM30 (30％ of methanol in the biodiesel-methanol blend) in the *** results show that,compared with those of biodiesel-methanol blend,the peak value of cylinder pressure increases,the second peak of heat release rate decreases,the start of second heat release are advanced,and the fuel economy and thermal efficiency are improved when CN improver is added to biodiesel-methanol ***,CO and HC emissions decrease,NOx emission varies little and smoke emissions increase ***,exhaust particles of BM30 mainly distribute in nanosize ***,particle number concentration decreases and peak of size distribution profile shifts toward large size direction.

关键词： biodiesel methanol common-rail (CR) dieselengine cetane number (CN) improver

来源：评论

学校读者我要写书评

暂无评论

Comparison of combustion characteristics of petroleum coke and coal in one-dimensional furnace

引用

中国高等学校学术文摘·能源与动力工程 2010年第3期4卷 436-442页

作者： Qulan ZHOU Qinxin ZHAO Guangjie ZHOU Huiqing WANG Tongmo XU Shien HUI State Key Laboratory of Multiphase Flow of Power Engineering Xi'an Jiaotong University Xi'an 710049 China

The effect of primary air fraction f1, outer secondary air swirl strength and excess oxygen coefficient on the combustion characteristics of petroleum coke, Hejin lean coal and Shenmu soft coal are researched on a one-dimensional furnace using a dual channel swirl burner. The results show that with the increase in primary air fraction f1, the NOx emission concentrations of both Hejin lean coal and petroleum coke increase, and the combustion worsens in the earlier stage, but the burn-out rate of Shenmu soft coal is improved. The NOx emission concentration obtains a minimum value with an increase in f1. The ignition and burn-out rate of petroleum coke and Shenmu soft coal are optimal when Ωdl is minimum and Ωdl=0.87, respectively. However, both the NOx emission concentration of petroleum coke and Shenmu soft coal are minimum when Ωdl=1.08. The increase in excess oxygen coefficient delays the ignition of petroleum coke, worsens the combustion condition and increases the NOx emission concentration, but it greatly decreases the NOx emission concentration of Shenmu soft coal.

关键词： petroleum coke Shenmu soft coal Hejin lean coal combustion characteristics experimental research

来源：评论

学校读者我要写书评

暂无评论

Numerical simulation of the heat flux distribution in a solar cavity receiver

引用

能源前沿 2011年第1期5卷 98-103页

作者： Yueshe WANG Xunwei DONG Jinjia WEI Hui JIN State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

In the solar tower power plant, the receiver is one of the main components of efficient concentrating solar collector systems. In the design of the receiver, the heat flux distribution in the cavity should be considered first. In this study, a numerical simulation using the Monte Carlo Method has been conducted on the heat flux distribution in the cavity receiver, which consists of six lateral faces and floor and roof planes, with an aperture of 2.0m×2.0m on the front face. The mathematics and physical models of a single solar ray's launching,reflection, and absorption were proposed. By tracing every solar ray, the distribution of heat flux density in the cavity receiver was obtained. The numerical results show that the solar flux distribution on the absorbing panels is similar to that of CESA-I's. When the reradiation from walls was considered, the detailed heat flux distributions were issued, in which 49.10% of the total incident energy was absorbed by the central panels,47.02% by the side panels, and 3.88% was overflowed from the aperture. Regarding the peak heat flux, the value of up to 1196.406 kW/m2 was obtained in the center of absorbing panels. These results provide necessary data for the structure design of cavity receiver and the local thermal stress analysis for boiling and superheated panels.

关键词： solar cavity receiver Monte Carlo method heat flux distribution

来源：评论

学校读者我要写书评

暂无评论

Numerical study on laminar flame speed of natural gas-carbon monoxide-air mixtures

引用

Frontiers of Chemical Science and engineering 2010年第4期4卷 411-416页

作者： Chen DONG Qulan ZHOU Qinxin ZHAO Tongmo XU Shi’en HUI State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

Laminar flame speeds of natural gas-carbon monoxide-air mixtures are calculated by CHEMKIN II with GRI Mech-3.0 over a large range of fuel compositions,equivalence ratios,and initial *** calculated results of natural gas are compared with previous experimental results that show a good *** calculated laminar flame speeds of natural gas-carbon monoxide-air mixtures show a nonmonotonic increasing trend with volumetric fraction of carbon monoxide and an increasing trend with the increase of initial temperature of *** maximum laminar flame speed of certain fuel blend reaches its biggest value when there is 92%volumetric fraction of carbon monoxide in fuel at different initial *** stoichiometric natural gas-carbon monoxide-air mixtures are selected to study the detailed chemical structure of natural gas-carbon monoxide-air *** results show that at stoichiometric condition,the fuel blend with 80%volumetric fraction of carbon monoxide has the biggest laminar flame speed,and the C normalized total production rate of methane with 80%volumetric fraction of carbon monoxide is the largest of the five stoichiometric mixtures.

关键词： laminar flame speed numerical study nonmonotonic increasing trend

来源：评论

学校读者我要写书评

暂无评论

Convective heat transfer in helical coils for constant-property and variable-property flows with high Reynolds numbers

引用

中国能源与动力工程前沿 2010年第4期4卷 546-552页

作者： Yufei MAO Liejin GUO Bofeng BAI Ximin ZHANG State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

Forced convection heat transfer of single-phase water in helical coils was experimentally studied. The testing section was constructed from a stainless steel round tube with an inner diameter of 10?mm, coil diameter of 300?mm, and pitch of 50?mm. The experiments were conducted over a wide Reynolds number range of 40000 to 500000. Both constant-property flows at normal pressure and variable-property flows at supercritical pressure were investigated. The contribution of secondary flow in the helical coil to heat transfer was gradually suppressed with increasing Reynolds number. Hence, heat transfer coefficients of the helical tube were close to those of the straight tube under the same flow conditions when the Reynolds number is large enough. Based on the experimental data, heat transfer correlations for both incompressible flows and supercritical fluid flows through helical coils were proposed.

关键词： convective heat transfer helical coils high Reynolds number supercritical pressure variable property

来源：评论

学校读者我要写书评

暂无评论

Hierarchical growth of a novel Mn-Bi coupled BiVO4 arrays for enhanced photoelectrochemical water splitting

引用

Nano Research 2019年第3期12卷 575-580页

作者： Lu Wang Jinzhan Su Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering School cf Energy & Power Engineering Xian Jiaotong University Xian 710049 China

Oxygen evolving catalyst (OEC) is a critical determinant for the efficiency of photoelectrochemical (PEC) water splitting. Here we report an approach to depositing a novel manganese borate (Mn-Bi) OER catalyst on BiVO4 nanocone photoanode by photodeposition in sodium borate buffer solution containing Mn(Ⅱ) ions. Due to the spontaneous photo-electric-field-enhancement effect at the vertically oriented BiVO4 nanocone structure, spherical Mn-Bi nanoparticle was selectively photodeposited at the apex of BiVO4 nanocone. Significant improvement of photocurrent was observed for the obtained hierarchical Mn-Bi/BiVO4 photoanode which could be ascribed to enhanced hole injection efficiency, especially in low bias region. It was observed that the injection efficiency of Mn-Bi/BiVO4 is 98% which gave a photocurrent of 0.94 mA/cm^2 at 1.5 V vs. RHE.

关键词： bismuth vanadate photoelectrochemistry solar water splitting oxygen evolution

来源：评论

学校读者我要写书评

暂无评论

Implementation of an efficient segregated algorithm-IDEAL on 3D collocated grid system

引用

Chinese Science Bulletin 2009年第6期54卷 929-942页

作者： SUN DongLiang QU ZhiGuo HE YaLing Tao WenQuan State Key Laboratory of Multiphase Flow in Power Engineering School of Energy & Power Engineering Xi'an Jiaotong University Xi'an 710049 China

The segregated algorithm-IDEAL (inner doubly-iterative efficient algorithm for linked-equations) is an efficient and stable algorithm. In this algorithm, there exist inner doubly-iterative processes for pres-sure equation, which almost completely overcome two approximations in SIMPLE algorithm. Thus the coupling between velocity and pressure is fully guaranteed, greatly enhancing the convergence rate and stability of iteration process. In this paper, implementation of the IDEAL algorithm on a 3D collo-cated grid system is conducted. The interface velocity is calculated by the modified momentum inter-polation method (MMIM), by which the converged result is independent of the under-relaxation factor. Finally, five three-dimensional incompressible fluid flow and heat transfer problems are provided to compare the convergence rate and robustness between the IDEAL and three other most widely-used algorithms (SIMPLER, SIMPLEC and PISO). By the comparison it can be concluded that the IDEAL al-gorithm is more robust and efficient than the three other algorithms.

关键词：隔离算法网格系统理想 SIMPLE算法 3D 压力方程收敛速度迭代过程

来源：评论

学校读者我要写书评

暂无评论

Simulation of combustion in spark-ignition engine fuelled with natural gas-hydrogen blends combined with EGR

引用

中国高等学校学术文摘·能源与动力工程 2009年第2期3卷 204-211页

作者： Jie WANG Zuohua HUANG Bing LIU Xibin WANG State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China

A numerical simulation of the influence of different hydrogen fractions, excess air ratios and EGR mass fractions in a spark-ignition engine was conducted. Good agreement between the calculated and measured in-cylinder pressure traces as well as pollutant formation trends was obtained. The simulation results show that NO concentration has an exponential relationship with temperature and increases sharply as hydrogen is added. EGR introduction strongly influences the gas temperature and NO concentration in the cylinder. The difference in temperature will lead to even greater difference in NO concentration. Thus, EGR can effectively decrease NO concentration. NO concentration reaches its peak value at the excess air ratio of 1.1 regardless of EGR mass fraction. The study shows that natural gas-hydrogen blend combined with EGR can realize a stable combustion and low NO emission in a spark-ignition engine.

关键词： natural gas hydrogen NO exhaust gas recirculation numerical simulation

来源：评论

学校读者我要写书评

暂无评论

Room-temperature photodeposition of conformal transition metal based cocatalysts on BiVO4 for enhanced photoelectrochemical water splitting

引用

Nano Research 2020年第1期13卷 231-237页

作者： Lu Wang Tao Zhang Jinzhan Su Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringSchool of Energy&Power EngineeringXi’an Jiaotong UniversityXi’an710049China

Photoelectrochemical(PEC)water splitting using semiconductors offers a promising way to convert renewable solar energy to clean hydrogen ***,due to the sluggish reaction kinetics of water oxidation,significant charge recombination occurred at the photoanode/electrolyte interface and cause decrease of its PEC *** reduce the surface recombination,we deposit different transition metal complexes on BiVO4 nanocone arrays by a versatile light driven in-situ two electrode photodeposition approach without applied *** cobalt phosphate“Co-Pi”,nickel borate“Ni-Bi”and manganese phosphate“Mn-Pi”complexes were deposited on BiVO4 nanocone arrays to form core-shell structure photoanode,all of which lead to enhanced photoelectrochemical *** photocurrent of the Co-Pi/BiVO4 photoanode under front-side illumination for 5 min is increased by 4 folds comparing to that of bare BiVO4 photoanode at 0.6 V ***,reaching a hole transfer efficiency as high as 94.5%at 1.23 V *** proposed photodeposition strategy is simple and efficient,and can be extended to deposite cocatalyst on other semiconductors with a valence band edge located at a potential more positive than the oxidation potential of transition metal ion in the cocatalyst.

关键词： bismuth vanadate photoelectrochemcial water splitting conformal photodeposition cocatalyst

来源：评论

学校读者我要写书评

暂无评论

Hydrodynamic Pattern in Drying Saline Droplet with Suspended Nanoparticles

引用

Journal of Bionic engineering 2020年第4期17卷 802-808页

作者： Junheng Ren Xin Zhong Lu Shen Fei Duan School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Evaporation of multicomponent droplets has gained much attention nowadays because of their complex flow fields and various deposition *** we observe strong flows in evaporating sodium chloride saline droplets with suspended alumina oxide *** evolution of flow pattern was studied by tracking the trajectories of particles and the velocity field was investigated with Particle Image Velocimetry *** non-uniform evaporation rate along the droplet surface leads to a concentration gradient which induces the convection *** the evaporation process before crystallization happens,evolution of the flow can be divided into two *** Regime I,a centrosymmetric convection recirculation is formed *** RegimeⅡ,the convection recirculation migrates to the droplet edge and evolves into several small *** the late evaporation stage,crystallization could induce strong convection *** is shown that the flow tends to become more chaotic with a lower salt concentration.

关键词： convection flow concentration gradient saline droplet crystallization

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：